• Title/Summary/Keyword: HAS-2

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Effect of $Ca^{2+}$ on Phvsiological Activites of the Acrosome Reaction on Spermatozoa ($Ca^{2+}$이 정자 첨체반응의 생리적 활성에 미치는 영향)

  • 장재호;오영근
    • The Korean Journal of Zoology
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    • v.39 no.2
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    • pp.182-189
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    • 1996
  • It has been known that spermatozoa should obtain their fertilizing ability through capacitation and acrosome reaction, and that in these processes of fertilization, Ca2+ platys an important role for their conjugation. Therefore the present study has been designed in order to clarify the effect of fluctuation of the media Ca2+ level and the intracellular concentration of the spermatozoa on the acrosomes. During the incubation of spermatozoa, a considerable fluctuation in the media Ca2+ level has been observed after the BSA administration and the media concentration of Ca2+. It is deduced that these fluctuation rates may have an effect on the acrosome reaction. The fluctuation of K+ flux has been observed in accordance with the incubation period over time, and it's concentration seems to be closely related with the acrosomal reaction. The respiratory exchange rate (RERI of the spermatozoa is kept more regular in the BSA and Cacl2 administration groups than the non-administration group. Based on the experimental findings, it is possible to deduce a hypothesis from these findings that physiological activities of the acrosome reaction are not functionally related to the media Ca2+ level and the intracellular influx of Ca2+ concentration, although Ca2+ platys an important role as a stimulating factor in the acrosome reaction.

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A Performance Analysis of I/O Scheduler for NAND Flash File System (NAND 플래시 파일시스템의 I/O 스케줄러 성능분석)

  • Lee, Yeongseok;Lee, Changhee;Chung, Kyungho;Kim, Yonghwan;Ahn, Kwangseon
    • Journal of Korea Society of Industrial Information Systems
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    • v.18 no.2
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    • pp.27-34
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    • 2013
  • NAND Flash Memory has been used in several devices by low cost and high capacity, and the demand for mass NAND Flash Memory has increased due to the multimedia extension of mobile devices. The JFFS2, NILFS2, and YAFFS2 file systems are used mainly in NAND Flash Memory. In this paper, the performance of Sequential read/write of the 3 file systems are analyzed for the 4 I/O schedulers : CFQ(Complete Fair Queuing) I/O scheduler, NOOP(No Operation) I/O scheduler, Anticipatory I/O scheduler, and Deadline I/O scheduler. In JFFS2 file system, Anticipatory I/O scheduler has the best performance by 8% decreasing speed in writing time and 1.5% decreasing speed in reading time compared to the other I/O scheduler. In YAFFS2 file system, it results are similar to performance in reading and writing for the 4 I/O schedulers. In NILFS2 file system, NOOP I/O scheduler has 2% faster in writing and Deadline I/O scheduler has 6% faster in reading than other I/O schedulers.

Design Optimization of Liquid Rocket Engine Using Genetic Algorithms (유전알고리즘을 이용한 액체로켓엔진 설계 최적화)

  • Lee, Sang-Bok;Lim, Tae-Kyu;Roh, Tae-Seong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.2
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    • pp.25-33
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    • 2012
  • A genetic algorithm (GA) has been employed to optimize the major design variables of the liquid rocket engine. Pressure of the main combustion chamber, nozzle expansion ratio and O/F ratio have been selected as design variables. The target engine has the open gas generator cycle using the LO2/RP-1 propellant. The gas properties of the combustion chamber have been obtained from CEA2 and the mass has been estimated using reference data. The objective function has been set as multi-objective function with the specific impulse and thrust to weight ratio using the weight method. The result shows about 4% improvement of the specific impulse and 23% increase of the thrust to weight ratio. The Pareto frontier line has been also obtained for various thrust requirements.

The Effects of Injection Molding Conditions of Polypropylene on the Linear Shrinkage and Weight of Molded Parts (폴리프로필렌의 사출성형조건이 성형품의 선형수축률과 중량에 미치는 영향)

  • 유중학;김희송
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.322-329
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    • 1995
  • Series of experimental work was performed to mold tensile specimens by using the injection molding machine Mold temperature, melt temperature and packing time were chosen as processing parameters for studying the effects of those conditions on the linear shrinkage of final product. Here, each processing variable was decided from the numerical simulation and resin manufacturer's suggested value. The effects of molding conditions on the linear shrinkage in flow direction of the resin were analyzed by measuring the parts 2, 10, 30 and 60 days after molding. As a result, the linear shrinkage increased with the higher mold and melt temperature, and the change of mold temperature has shown more influence. The linear shrinkage of polypropylene has been found to progress up to 30 day with the lapse of the time, and the amount of the linear shrinkage has shown to be between 2.14% and 2.75%. In addition, the effects of packing pressure on the weight has shown to be extremely significant up to freezing time, and proper packing time of the tensile specimen has been found to be 2.0 seconds.

Photocatalytic and Sonophotocatalytic degradation of alachlor using different photocatalyst

  • Bagal, Manisha V.;Gogate, Parag R.
    • Advances in environmental research
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    • v.2 no.4
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    • pp.261-277
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    • 2013
  • The degradation of alachlor has been investigated using sonolysis (US), photocatalysis (UV) and sonophotocatalysis (US/UV) using three photocatalyst viz. $TiO_2$ (mixture of anatase and rutile), $TiO_2$ (anatase) and ZnO. The effect of photocatalyst loading on the extent of degradation of alachlor has been investigated by varying $TiO_2$ (both types) loading over the range of 0.01 g/L to 0.1 g/L and ZnO loading over the range of 0.05 g/L to 0.3 g/L. The optimum loading of the catalyst was found to be dependent on the type of operation i.e., photocatalysis alone or the combined operation of sonolysis and photocatalysis. All the combined processes gave complete degradation of alachlor with maximum rate of degradation being obtained in the case of sonophotocatalytic process also showing synergistic effect at optimized loading of photocatalyst. About 50% to 60% reduction in TOC has been obtained using the combined process of sonophotocatalysis depending on the operating conditions. The alachlor degradation fitted first order kinetics for all the processes under investigation. It has been observed that the $TiO_2$ (mixtrure of anatase and rutile) is the most active photocatalyst among the three photocatalysts studied in the current work. The effect of addition of radical enhancers and scavengers on sonophotocatalytic degradation of alachlor has been investigated in order to decipher the controlling mechanism. The alachlor degradation products have been identified using LC-MS method.

A Small-Area Hardware Implementation of Hash Algorithm Standard HAS-160 (해쉬 알고리듬 표준 HAS-l60의 저면적 하드웨어 구현)

  • Kim, Hae-Ju;Jeon, Heung-Woo;Shin, Kyung-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.3
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    • pp.715-722
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    • 2010
  • This paper describes a hardware design of hash function processor which implements Korean Hash Algorithm Standard HAS-160. The HAS-160 processor compresses a message with arbitrary lengths into a hash code with a fixed length of 160-bit. To achieve high-speed operation with small-area, arithmetic operation for step-operation is implemented by using a hybrid structure of 5:3 and 3:2 carry-save adders and carry-select adder. It computes a 160-bit hash code from a message block of 512 bits in 82 clock cycles, and has 312 Mbps throughput at 50 MHz@3.3-V clock frequency. The designed HAS-160 processor is verified by FPGA implementation, and it has 17,600 gates on a layout area of about $1\;mm^2$ using a 0.35-${\mu}m$ CMOS cell library.

The Thermal Aging Characteristics of Cellulose Paper using Analysis for CO, $CO_2$ Gas and Furan Compounds (CO, $CO_2$ 가스와 Furan 함유량의 분석을 통한 셀룰로오스 절연지의 열 열화특성)

  • Kim, Jae-Hoon;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.4
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    • pp.499-504
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    • 2009
  • The analysis for furan compound has provided a complementary technique to dissolved gas analysis(DGA) for monitoring transformers when total concentration of CO and $CO_2$ dissolved in oil only has been evaluated the aging of insulating paper. But, the analysis of furanic compounds by high performance liquid chromatography(HPLC) has been important more than DGA recently. Because it has been known that furanic components in transformer oil have come only from the decomposition of insulating paper. Therefore we have manufactured accelerating aging cell which was aged during 60 hours at 100, 150, 180 and $200^{\circ}C$, respectively, for investigating the characteristics of cellulose paper by thermal using analysis for CO, $CO_2$ and furan compound.

OPF considering CO2 emission constraints and the emission trading mechanism (CO2 배출제약 조건과 배출권 거래제를 고려한 OPF)

  • Kim, Yang-Il;Han, Seok-Man;Chung, Koo-Hyung;Park, Kyung-Han;Kim, Bal-Ho H.
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.343-344
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    • 2006
  • Consumption of fossil fuel has been increasing steadily, and it has seriously affected environment. Due to this situation, UN establish ed UNFCC (United rations Framework Convention on Climate Change), and since Feb. 2005, Kyoto Protocol has come into effect for UNFCC obligation. In Korean power system, coal and oil thermal generation emitting large CO2 form about 46% of total generation. Moreover since electricity dem and has been increasing continuously, various alternatives should be designed to comply with Kyoto Protocol. In this paper, we analyze changes of each GENCO's generation pattern and resource planning under CO2 emission constraints. For this analysis, we incorporate CO2 emission constraints and the emission trading mechanism into the conventional OPF model.

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A Study on Ferrite Stainless Steel Corrosion Resistance or Mechanical Characteristics of 434LD2 ABS Sensor Ring (센서 링이 내식성과 기계적 특성에 관한 연구)

  • 양현수;금영준;정풍기
    • Journal of the Korea Safety Management & Science
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    • v.5 no.1
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    • pp.129-141
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    • 2003
  • In this thesis, using the 400 series ferrite stainless steel such as 434LD$_2$ which are furter excellent then the existing ferric products in mechanical characteristics, and experiment has been conducted on corrosion resistance of sensor ring. The results are following. 1. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition. 2. 434LD$_2$ ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 3. As hardness value of $H_{RB}$ 80 and tensile test, 434LD$_2$ ferrite stainless steel with show a good endurance when it is combined to constant velocity joint (c/v joint), and has a good hardness properties endurable to sand and pebble impact.

Fabrication of vertical Hall sensor for detecting three phases magnetic field (3상의 자계 검출을 위한 수직 Hall 센서의 제작)

  • Lee, Ji-Yeon;Nam, Tae-Chul
    • Journal of Sensor Science and Technology
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    • v.14 no.2
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    • pp.85-90
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    • 2005
  • In this study, we have fabricated a three branches vertical Hall sensor for detecting three phases rotation informations of miniaturized brushless motor. The sensor gives three position signals phase shifted by $120^{\circ}$, corresponding to the motor driving signals. The branch has one Hall output and one input each other. The central part acts as common driving input. Sensor has branch width of $150{\mu}m$ and distance from central electrode to Hall electrode of $100{\mu}m$. The sensitivity of sensor is 250 V/$A{\cdot}T$ at magnetic field of 0.1 T. It has also showed three sine waves of Hall voltages with $120^{\circ}$ phase over a $360^{\circ}$ rotation. A packaged sensing part are $2{\times}2mm^{2}$ and has been successfully tested on a motor rotation at a speed up to 60,000 rpm.